What is Merrill hiding?

"Merrill's selection of Thain was a surprise because the firm had recently indicated to BlackRock CEO Larry Fink that the job was his if he wanted it. CNBC has learned that Fink said he would take the job but only if Merrill did a full accounting of its subprime exposure. At that point, Merrill, which owns 49% of BlackRock, moved in a different direction and decided to go with Thain instead."